Microsoft.CodeAnalysis.Metrics was unintentionally added to nupkg dependencies - roslyn

Question

I added a NuGet packages 'Microsoft.CodeAnalysis.Metrics' (v2.9.8) to my project to measure code metrics.
Just I wanted to measure code metrics, I don't mean to write any code depends the library.
Then I created nupkg with nuspec below,
<?xml version="1.0"?>
<package >
<metadata>
<id>$id$</id>
<version>$version$</version>
<title>$title$</title>
<authors>$author$</authors>
<owners>$author$</owners>
<!--
<licenseUrl>http://LICENSE_URL_HERE_OR_DELETE_THIS_LINE</licenseUrl>
<projectUrl>http://PROJECT_URL_HERE_OR_DELETE_THIS_LINE</projectUrl>
<iconUrl>http://ICON_URL_HERE_OR_DELETE_THIS_LINE</iconUrl>
-->
<requireLicenseAcceptance>false</requireLicenseAcceptance>
<description>$description$</description>
<releaseNotes>First release of this library.</releaseNotes>
<copyright>Copyright (c) 2018 My Company.</copyright>
<tags></tags>
<dependencies>
<group targetFramework=".NETFramework4.5.2" />
</dependencies>
</metadata>
</package>
Next I created with a command NuGet.exe pack MyCompany.MyProject.csproj, and a nupkg generated.
After that I checked the nupec included in the generated nupkg.
The nuspec is below:
<?xml version="1.0" encoding="utf-8"?>
<package xmlns="http://schemas.microsoft.com/packaging/2013/05/nuspec.xsd">
<metadata>
<id>MyCompany.MyProject</id>
<version>1.0.0</version>
<title>MyCompany.MyProject</title>
<authors>My Company.</authors>
<owners>My Company.</owners>
<requireLicenseAcceptance>false</requireLicenseAcceptance>
<description>MyCompany.MyProject is a example.</description>
<releaseNotes>First release of this library.</releaseNotes>
<copyright>Copyright (c) 2018 My Company.</copyright>
<dependencies>
<dependency id="Microsoft.CodeAnalysis.Metrics" version="2.9.8" />
</dependencies>
</metadata>
</package>
There was a dependency to Microsoft.CodeAnalysis.Metrics unintentionally.
I also added a NuGet package 'Microsoft.CodeAnalysis.FxCopAnalyzers' as well, but it wouldn't apprear in the generated nuspec. I don't know the difference.
I would like to avoid to be added any dependency libraries to nupkg dependencies, except libraries which my project depends on.
How can I make it as I intend.
Is it a problem of the 'Microsoft.CodeAnalysis.Metrics'? Should I report to the developers?